JP2021518033A - Solid electrolyte material - Google Patents

Abstract

The present invention relates to an electrically non-conductive solid electrolyte material (F1) for an electrochemical secondary battery, wherein the solid electrolyte material has pores (2).

Description

The present invention relates to an electrically non-conductive solid electrolyte material for an electrochemical secondary battery, a method for producing an electrode for an electrochemical secondary battery and an electrochemical secondary battery.

Solid separators for gas diffusion electrodes are known from the prior art, and solid separator materials have continuous channels (see EP1345280A1). Further, a lithium (Li) ion conductive solid electrolyte that can be used as a separator is known. W. The document "All-Solid State Battery" by Weppner in Secondary Batteries-Lithium Rechargeable System, 2009, Elsevier shows the layer structure of a Li-ion battery using a lithium-ion conductive solid electrolyte material as a separator. And will be created using the vapor deposition method.

EP1345280A1 "All-Solid State Battery" by W. Weppner in Secondary Batteries-Lithium Battery System, 2009, Elsevier

An object of the present invention is to manufacture an improved electrically non-conductive solid electrolyte material for an electrochemical secondary battery, an improved electrochemical secondary battery and an electrode for an electrochemical secondary battery. Is to disclose an improved method for.

An object of the present invention is the method for producing an electrically non-conductive solid electrolyte material according to claim 1, an electrochemical secondary battery according to claim 9, and an electrode for an electrochemical secondary battery according to claim 10. Achieved. Advantageous embodiments of the present invention and further development are due to the dependent claims.

According to the present invention, the electrically non-conductive solid electrolyte material (electrically non-conductive solid electrolyte material) for an electrochemical secondary battery has pores (pores).

The pores can be connected to each other, but the continuous channels formed by the pores through the solid electrolyte material are optional. The preferred diameter of the pores is 10 nm to 50 μm, and the range of 800 nm to 30 μm is particularly advantageous for use in electrochemical secondary batteries such as Li-ion batteries.

According to one embodiment of the invention, the electrode for an electrochemical secondary battery comprises such an electrically non-conductive solid electrolyte material and an active material, wherein the particles of the active material are electrically. The pores of the first subset of pores located in the first portion of the non-conductive solid electrolyte material are at least partially filled, and the second portion of the electrically non-conductive solid electrolyte material. The pores located in are not filled.

This means that not all pores are filled with particles of the active substance, but only the pores of a particular part of the solid electrolyte material-the first part. is doing. The pores of the other portion of the solid electrolyte material-the second portion-are unfilled (unfilled). In this regard, unfilled means that these pores are loaded with a gaseous medium, such as the noble gas argon. Therefore, in the second part, unfilled pores are located, which are ionic and electrically non-conductive. The terms "ionic conductivity" and "electrically non-conductive" relate to the classification of these terms well known to those of skill in the art in the field of electrochemical energy storage technology. The electrolyte typically has (Li) ionic conductivity and the separator has electrical non-conductivity.

The first portion of the solid electrolyte material with a partial amount of pores filled with particles of the active substance is electrically conductive. This is because, in this region, the particles of the electrically conductive active substance are electrically conductively connected to each other. Conductive carbon black and / or conductive graphite can be added to the active material to optionally reinforce the electrical conductivity of the active material.

Also, the electrodes contain conductive carbon black (and / or conductive graphite), and the particles of conductive carbon black are placed in the pores located in the first portion of the electrically non-conductive solid electrolyte material. A third subset of pores located at least partially filled in the pores of the two subsets and the active material and conductive carbon black particles located in the first portion of the electrically non-conductive solid electrolyte material. It is also advantageous when the pores of the above are at least partially filled.

In this way, it is achieved that the electrical conduction properties in the first part of the solid electrolyte material are further improved. This is because the pores in the first portion can be filled with particles of active material, particles of conductive carbon black, or both types of particles. This does not exclude the possibility that a subset of pores may also be present in the first portion. The subset of pores is neither filled with particles of active material nor particles of conductive carbon black.

According to an advantageous embodiment of the present invention, the electrically non-conductive solid electrolyte material for an electrochemical secondary battery has pores only in portions, i.e., pores in at least one portion. do not have. The solid electrolyte material has its crystal density in the non-porous portion. In other words, the material in the non-porous part is compact.

Therefore, the solid electrolyte material has a portion in which it is porous and at least one portion in which it is non-porous, i.e. a compact portion. Isolated pores, that is, dissociated pores that remain, for example, when the material cannot be produced consistently and compactly, also fall under the scope of the present disclosure.

According to a particularly preferred embodiment of the present invention, the electrodes for an electrochemical secondary battery include such a partially non-porous solid electrolyte material and an active material, wherein the particles of the active material are electric. The pores of the first subset of pores located in the porous portion of the non-conductive solid electrolyte material are at least partially filled.

Therefore, some pores in the porous portion of the solid electrolyte material are at least partially filled with particles of the active material, i.e., a single filled pore is only partially filled with the active material. Can be done. Subsets of pores may remain, but they are not filled with the active substance. The non-porous portion of the solid electrolyte material serves both as a Li ion conductor and as a separator.

According to a preferred further development, the electrodes for the electrochemical secondary battery also contain carbon black, and the particles of the active substance are the first of the pores located in the porous portion of the electrically non-conductive solid electrolyte material. The pores of a subset of are at least partially filled, and the carbon black particles, at least partially, fill a second subset of pores located in the porous portion of the electrically non-conductive solid electrolyte material. However, the active material and carbon black particles at least partially fill the pores of a third subset of pores located in the porous portion of the electrically non-conductive solid electrolyte material.

In the context of the present disclosure, alternatives to conductive carbon black are also conductive graphite, carbon nanotubes, or other metal additives such as nanowires.

Therefore, in the porous portion of the solid electrolyte material, the pores can be divided into four subsets. A subset of pores picks up particles of active material, another subset picks up particles of conductive carbon black, yet another subset picks up particles of active material and conductive carbon black, and a fourth subset of pores picks up particles. It remains unfilled. Ideally, the subset of pores with particles and conductive carbon black is the major subset (> 90%) of the pores.

According to the present invention, further, positive conductors (eg, aluminum foil), positive electrodes with positive active material and conductive carbon black, negative conductors with conductive carbon black and negative active material (eg, negative active material). Copper foil), and as a separator, an electrically non-conductive solid that has pores in the first and third portions and is non-porous in the second portion adjacent to the first and second portions. Electrochemical secondary batteries containing electrolyte materials are described. The particles of the negative active substance at least partially fill the pores of the first subset of pores located in the first portion of the electrically non-conductive solid electrolyte material. The conductive carbon black particles at least partially fill the pores of the second subset of pores located in the first portion of the electrically non-conductive solid electrolyte material, negatively active material and conductive. The carbon black particles at least partially fill the pores of a third subset of pores located in the first portion of the electrically non-conductive solid electrolyte material. The particles of the positive active substance at least partially fill the pores of the first subset of pores located in the third portion of the electrically non-conductive solid electrolyte material. The conductive carbon black particles at least partially fill the pores of the second subset of pores located in the third portion of the electrically non-conductive solid electrolyte material, positively active material and conductive. The particles of carbon black fill at least partially the pores of a third subset of the pores located in the third portion of the electrically non-conductive solid electrolyte material. The non-porous second portion of the solid electrolyte material lies between the first and third portions of the solid electrolyte material.

In this way, an electrochemical secondary battery having an electrically non-conductive solid electrolyte material as a separator between the two electrodes is formed. This substance acts as a Li-ion conductor, and in each case has pores close to the electrodes, in which the respective active substances and conductive carbon black particles are incorporated. In such a secondary battery, the ion contact resistance between the active material and the electrolyte and, macroscopically, between the composite electrode and the separator is minimized. This is because the effective interface between the active material and the solid electrolyte is extremely widened compared to the layered or separate arrangement of the active material and the electrolyte material.

The present invention further relates to the manufacture of electrodes for electrochemical secondary batteries. We propose a procedure with the following steps:
Mixtures of step precursor materials and electrically active materials that provide precursor materials for non-conductive solid electrolyte materials with electrically active materials and optionally conductive materials such as conductive carbon black. Steps to homogenize,
Steps to compress a mixture of precursor material and electrically active material,
The step of sintering the compressed mixture into a sintered composite with a plate structure or rolling the compressed mixture into a rolled composite with a plate structure.
The precursor material is applied to the first surface of the plate structure of the sintered or rolled composite, and the precursor material on the plate structure of the sintered or rolled composite is compressed and sintered or rolled. Sintered or rolled composite with step precursor material applied to form a layer of precursor material on the plate-like structure of the composite step Sintered or rolled with step precursor material applied A metal foil is vapor-deposited on the second surface of the plate-like structure of the sintered or rolled composite (vacuum vapor deposition), or the sintered or rolled composite is used as a conductor on the metal foil. The process of pressing.

As a result of the method, an electrode is obtained in which the active material firmly adhered to the solid electrolyte material is applied (coated) on the conductor, and the solid electrolyte material forms a support matrix of the active material. The active substance is incorporated into the pores of the solid electrolyte material. The pore diameter is 10 nm to 50 μm. On the surface away from the conductor, the electrode is further covered with a solid electrolyte material, which is tightly bound to the solid electrolyte material forming the support matrix by the second sintering step, but has no pores. The portion or portion of the electrolyte material can serve as a separator for the electrodes when used in an electrochemical secondary battery.

The present invention is based on the following considerations:
All solid-state lithium or lithium-ion batteries (ASS-LZ) have advantages for use in the automotive environment. When the ASS-LZ is destroyed (eg, in the event of a corresponding serious accident due to mechanical, thermal or electrical stress), potentially toxic or flammable species are generated or released. These are considered to be extremely safe, as they do not.

According to the prior art, the conventional ASS-LZ has an interface between the active material of the positive electrode and the separator between the active material of the negative electrode and the separator. Typically, the active material and the separator material form a planar parallel layer with corresponding interfaces, each of which is essentially formed by a planar surface. Such an intrinsic interface has the drawback of forming a contact resistance with respect to the lithium (Li) ion conductivity in the battery. Li ions must be able to move rapidly across the interface. Otherwise, a transition potential or overvoltage will occur. The transition potential between the electrode and the separator is not desirable as it impedes the reactivity of the battery. As a result, this leads to, for example, poor performance on charge and the general high current behavior of the ASS-LZ. However, the key characteristics of ASS-LZ in automotive applications are high charge capacity and discharge capacity.

Therefore, according to the present invention, it is proposed to use an inorganic Li ion conductive solid material that can act as a separator and an electrolyte in a solid compound with an active material, particularly a cathode (positive) active material. .. The separator is porous in the area of the active substance of the electrode, and the pores of the separator also function as an electrolyte and are filled with particles of the active substance and, in some cases, conductive carbon black. Between the two electrodes there is a portion of the separator that has no pores or has pores that are not filled with the active substance and conductive carbon black.

In other words, the active material is embedded in the solid electrolyte material, or according to an alternative approach, the spaces in the active material are interspersed with the solid electrolyte material. The advantage of such a structure is that, in contrast to the layered structure of the active material and the separator, the interaction interface between the active material and the solid electrolyte is increased, resulting in a minimum total resistance to ionic conduction. .. Li ions can also interact with the solid electrolyte "inside" the active material layer and thus move from the active material to the solid electrolyte material. Within the solid electrolyte material, Li ions are conducted to the opposite polar active material without leaving the solid structural region of the solid electrolyte material.

Such a structure can also be referred to as a functionalized ceramic or a hybrid ceramic. Functionalization is indicated by the active substance introduced into the pores. In order to produce such a composite structure of an active substance and a solid electrolyte, it is necessary to prepare a porous structure in an electrolyte material suitable for accommodating the active substance and / or conductive carbon black. Inorganic and ceramic-based separators have been considered as materials for such solid electrolytes. For this purpose, the precursor of the solid electrolyte material is mixed with the active material particles and sintered. All common, such as layered transition metal oxides, olivine or spinel (cathodes), and graphite, silicon, metallic lithium, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) or carbon materials (anodes). Combination with a type of active substance is conceivable.

The structure thus manufactured has low ion contact resistance when operating the ASS-LZ, thus ensuring a high electrical output and a long service life of the ASS-LZ. This increases the weight and volumetric power densities compared to batteries with a prior art layered structure.

Suitable embodiments of the present invention are described below with reference to the accompanying figures. This provides further details, preferred embodiments and developments of the present invention. Details are schematically shown.
FIG. 1 shows an electrically non-conductive solid electrolyte having a filled pore region and an unfilled pore region.
FIG. 2 shows an electrically non-conductive solid electrolyte having a filled pore region and a non-pore region.
FIG. 3 is an electrochemical secondary battery having a pore region filled with a positive active substance, a pore region filled with a negative active substance, and a region without intermediate pores.

FIG. 1 shows a ceramic solid electrolyte material having a garnet structure (F1) having pores (2) having a diameter of 800 nm to 30 μm. The pores of the first region (A) are filled with the positive active substance NMC (3) and conductive carbon black (4), and not all pores are completely filled, or It's not completely unfilled. However, about 95% of the pores in this portion are at least partially filled. In the second region (B1) adjacent to the first region (A), the pores are not filled with either active material particles or conductive carbon black.

FIG. 2 is an exemplary embodiment different from FIG. 1 in that the second region (B2) of the solid electrolyte material (F2) adjacent to the first region (A) is non-porous. An embodiment is shown.

FIG. 3 shows a lithium ion battery (10) having a copper conductor (7) and an aluminum conductor (6). The ceramic solid electrolyte material (F3) acts as a separator (B2') between the negative active material (5) and the positive active material (3). The positive active material fills the pores (2) in the solid electrolyte material in the region (A') close to the aluminum conductor with conductive carbon black (4), thereby forming a positive electrode. The negative active material graphite and conductive carbon black fill the pores located near the copper conductor in the region (C'), thereby forming a negative electrode. This region (B2') has no pores, is located between the region (A') and the region (C'), and inherits the function of the separator in the battery.

Another embodiment relates to a method of manufacturing electrodes for a lithium ion battery. The material Li ₇ La ₃ Zr ₂ O ₁₂ is selected as the solid electrolyte material in the garnet structure. A mixture of lanthanum and zirconium oxide is used as a precursor for Li ₇ La ₃ Zr ₂ O _12. Synthetic graphite can be considered when the electrode production is used, for example, as an anode in a Li-ion battery. NMC111 can be considered when manufacturing the electrodes, for example, as a cathode (cathode) in a Li-ion battery. For that purpose, about 34 g of a precursor having an average particle size of 0.1 μm and about 98 g of NMC 111 having an average particle size of 9 μm are mixed and compressed together with about 3 g of conductive carbon black. For the sintering process in the nitrogen atmosphere, the temperature reaches about 400 to 1200 ° C. over about 24 hours under isobaric pressure. Under these conditions, the ceramic solid electrolyte material having a garnet structure maintains a stable state. _{In the following, 50 g of Li 7} La ₃ Zr ₂ O ₁₂ precursor material was applied (coated) to one side of the sintered structure, compressed with the above parameters, and sintered. An electrode structure as shown in FIG. 2 can be obtained. When manufacturing a cathode as in this example, aluminum is then deposited as a conductor material in the form of a film. For vaporization, it is desirable to use a vacuum evaporator having a melting tank temperature in the region of the melting point of aluminum and a vacuum of 10-3 mbar to 1 mbar.

Other solid electrolyte materials for other embodiments are perovskite, sulfides and oxides in addition to garnet. In particular, structures derived from LISICON (lithium (Li) Super (S) ions (I) conductor (CON)), for example, thio _{-LISICON Li 4-x M 1-} y M 'y S 4, wherein , M = Si, Ge, P, M'= P, Al, Zn, Ga, Sb, or NASISCON (sodium (Na) super (S) ion (I) of _{the general formula AMM'P 3} O ₁₂ ) Conductor (CON)), where A = Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , H ⁺ , H ₃ O ⁺ , NH ⁴⁺ , Cu ⁺ , Ag ⁺ , Pb ²⁺ , Cd ²⁺ , Mn ²⁺ , Co ²⁺ , Mn ²⁺ , Co ²⁺ , Ni ²⁺ , Zn ²⁺ , Al ³⁺ , Ln ³⁺ , Ge ⁴⁺ , Zr ⁴⁺ , Hf ⁴⁺ , Or empty, M and M'= divalent, trivalent, tetravalent, pentavalent transition metal ions, Zn ²⁺ , Cd ²⁺ , Ni ²⁺ , Mn ²⁺ , Co ²⁺ , Fe ³⁺ , Sc ³⁺ , ^{Ti 3+, V 3+, Al 3+} , In 3+, Ga 3+, Y 3+, Lu 3+, Ti 4+, Zr 4+, Hf 4+, Sn 4+, Si 4+, Ge 4+, V 5+, Nb 5+, Ta 5+, Sb 5+ , As ⁵⁺ , the phosphorus can be partially replaced by Si or As.

Claims (10)

-The solid electrolyte material has pores (2).
An electrically non-conductive solid electrolyte material (F1) for an electrochemical secondary battery. -The solid electrolyte material has pores in the parts (A, A', C') and
-The solid electrolyte material is characterized by having no pores in the portions (B2, B2').
An electrically non-conductive solid electrolyte material (F2, F3) for an electrochemical secondary battery. The electrically non-conductive solid electrolyte material according to claim 1, wherein the pore diameter is 10 nm to 50 μm. The electrically non-conductive solid electrolyte material according to claim 2, wherein the pore diameter is 10 nm to 50 μm. The electrode contains the active material (3) and contains
-The electrode comprises the electrically non-conductive solid electrolyte material according to claim 3 or 1.
-Particles of the active material fill at least partially the pores of the first subset of pores located in the first portion (A) of the electrically non-conductive solid electrolyte material.
-The pores located in the second part (B1) of the electrically non-conductive solid electrolyte material are unfilled,
An electrode for an electrochemical secondary battery, which is characterized in that. Electrodes contain conductive carbon black (4)
-The conductive carbon black particles at least partially fill the pores of the second subset of pores located in the first portion (A) of the electrically non-conductive solid electrolyte material.
-The particles of the active material and the particles of the conductive carbon black at least partially occlude the pores of a third subset of the pores located in the first portion (A) of the electrically non-conductive solid electrolyte material. Fill,
The electrode for an electrochemical secondary battery according to claim 5, wherein the electrode is characterized by this. The electrode contains the active material (3) and contains
-The electrode comprises the electrically non-conductive solid electrolyte material according to claim 4 or 2.
-The particles of the active material are characterized by at least partially filling the pores of a first subset of pores located in the first portion (A) of the electrically non-conductive solid electrolyte material. Electrodes for electrochemical secondary batteries. Electrodes contain conductive carbon black (4)
-The conductive carbon black particles at least partially fill the pores of the second subset of pores located in the first portion (A) of the electrically non-conductive solid electrolyte material.
-The particles of the active material and the particles of the conductive carbon black at least partially occlude the pores of a third subset of the pores located in the first portion (A) of the electrically non-conductive solid electrolyte material. Fill,
7. The electrode for an electrochemical secondary battery according to claim 7. An electrochemical rechargeable battery containing a positive electrode having a conductor (6) and a positive active material (3), a negative electrode having a conductor (7) and a negative active material (5), and a conductive carbon black (4). Next battery (10)
-Electrochemical secondary batteries contain an electrically non-conductive solid electrolyte material (F3) as a separator.
-The electrically non-conductive solid electrolyte material has pores in the parts (A', C') and has pores.
-The electrically non-conductive solid electrolyte material is non-porous (B2') in at least one portion and
-Particles of the positive active substance fill at least partially the pores of the first subset of pores located in the first portion (A') of the electrically non-conductive solid electrolyte material.
-The conductive carbon black particles at least partially fill the pores of the second subset of pores located in the first portion (A') of the electrically non-conductive solid electrolyte material.
-The positive active substance particles and the conductive carbon black particles at least partially cover the pores of a third subset of the pores located in the first portion (A') of the electrically non-conductive solid electrolyte material. Filled with
-Negative active substance particles at least partially fill the pores of the first subset of pores located in the first portion (C') of the electrically non-conductive solid electrolyte material.
-The conductive carbon black particles at least partially fill the pores of a second subset of pores located in the first portion (C') of the electrically non-conductive solid electrolyte material.
-Negative active substance particles and conductive carbon black particles are at least a portion of the pores of a third subset of pores located in the first portion (C') of the electrically non-conductive solid electrolyte material. The electrochemical secondary battery, which is characterized in that it is filled with particles. -Steps to provide precursor material for non-conductive solid electrolyte materials,
-The step of mixing the precursor material with the electrically active material,
-Steps to compress a mixture of precursor material and electrochemically active material,
-Steps of sintering a compressed mixture of precursor material and electrochemically active material into a plate-like sintered complex,
-A step of applying a precursor material to the first surface of a plate-like structure, compressing the precursor material on the plate-like structure, and forming a layer of the precursor material on the plate-like structure-the plate-like structure and the precursor Steps of Sintering Layers of Body Material-A method for making electrodes for electrochemical secondary batteries, comprising the step of depositing metal foil on the second surface of a plate-like structure.

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